This application relates to commonly assigned, copending applications Ser. No. 826,953 filed 2/7/86 "Control System for Engine Operation Using Two Fuels of Different Volumetric Energy Content" and Ser. No. 826,959 filed 2/7/86 entitled "Spark Timing Control of Multiple Fuel Engine", filed on even date herewith.
1. Field of the Invention
This invention relates to a method for controlling the utilization of a fuel mixture containing more than one type of fuel in an internal combustion engine.
2. Prior Art
U.S. Pat. No. 3,750,635 issued to Hoffman et al teaches a fuel control system for an internal combustion engine that may use one of a number of different grades of fuel, such as diesel and turbine fuels. The system uses a light source and a pair of photocells to measure the light transmission of the particular fuel being used to adjust the amount of fuel supplied to the engine.
U.S. Pat. No. 4,369,736 issued to Ito teaches a control system for an engine using a blend of gasoline and alcohol in which an increasing amount of hot air is admitted to the induction system as the concentration of the alcohol increases, thereby providing proper atomization of the fuel. An alcohol sensor detects the concentration of the alcohol in the fuel and provides a signal to an electronic control unit which opens a control valve to allow more hot air heated by the exhaust manifold to pass into the nose of the air cleaner and then to the carburetor. The alcohol sensor detects the concentration of alcohol by a change in the electrostatic capacity of the fuel.
U.S. Pat. No. 4,323,046 issued to Barber teaches a dual fuel blend system having a first liquid storage tank for containing a petroleum fuel and a second liquid storage tank for containing a nonpetroleum fuel.
U.S. Pat. No. 4,438,749 issued to Schwippert teaches the use of a fuel sensor using an index of light refraction to determine the ratio of gasoline and alcohol in a particular fuel. The sensor emits a signal as a variable for the control of a dosage device of the air fuel ratio. An electronic circuit is connected to the sensor to control the dosage device in accordance with the determined state or composition.
Japanese publication No. 56-165772 teaches a system for adjusting the ignition timing of an engine which is supplied with a mixture of gasoline and alcohol. An alcohol concentration sensor using a capacitor provides a signal to an alcohol concentration detection circuit to advance the ignition timing when the concentration of the alcohol has exceeded a predetermined amount.
U.S. Pat. No. 4,031,864 issued to Crothers teaches supplying an engine with a multiple fuel which is phase separable to form a two-phase liquid and supplying the combustion engine with liquid selected from the liquid withdrawn from the upper phase, the liquid withdrawn from the lower phase, and liquid withdrawn from both the upper phase and the lower phase.
There still remains a need for an improved method of controlling the amount of a fuel mixture having at least two different fuels, to be supplied to an internal combustion engine. These are some of the problems this invention overcomes.